Antagonistic action of reductants against vanadate-induced EP decrease.

The antagonistic action of ascorbic acid or glutathione against vanadate was studied by observing changes in EP in guinea pig cochlea. After intravenous injection of ascorbic acid or glutathione, the EP decrease induced by perfusion of the perilymphatic space with vanadate solution was suppressed and the EP showed a remarkable recovery in some animals. Intravenous preadministration of either of the two compounds inhibited or prevented the vanadate-induced EP decrease. When ascorbic acid or glutathione was added to the vanadate solution, the EP decrease was also inhibited. The chemical action of both reductants against vanadate is discussed. From the results obtained, it is speculated that a chemical balance between some oxidants and reductants in the stria vascularis, must be kept constant in order to maintain the EP at a constant potential level.